Study of transient-based phase selection for EHV transmission line relaying

A new method of transient-based faulty phase selection for EHV transmission lines is presented in this paper. This method stems from analyzing the coupling relation among three phase conductors. Firstly the transient energy of current faulty component in each phase is represented with the wavelet transform. Then the transient energy magnitudes among three phases are compared to classify the fault type and identify the faulty phase(s). The performance of this faulty phase selection algorithm has been extensively tested using EMTP. Test results show that the new approach can select faulty phase(s) correctly and quickly in case of various fault conditions involving different positions, path resistances as well as inception angles. The dynamic simulation data have also fully validated the feasibility of the newly proposed faulty phase selection scheme. To some extent, the approach can make up some deficiencies of initial traveling-wave based faulty phase selection schemes. (6 pages)